Sending Wi-Fi from Mac-Mini to Wii

I'm from the US but I'm now living in Brazil. One of the bad things from here is the horrible and expensive internet. My only option is a 3G modem from a cell phone provider, and as we all know, they don't play nicely with Wi-Fi routers, including my own. I was wondering if there were any ways to send internet from my Mac-Mini (2nd Gen equipped with AirPort Card) to my Nintendo Wii, using either a wireless or wired connection (I have a LAN to USB adapter for my Wii). I have been able to create a network between the two, but that doesn't work for sending internet, I guess just for sharing files or something of the sort. PLEASE HELP ME!!! IM NOT A COMPUTER WIZ AND I NEED MY DAILY FIX OF ONLINE GAMING!!!